Are you running the beta Sonoma as your primary operating system, or are you running it as a virtualized operating system? I know that virtualized systems can not support MRIcroGL or FSLeyes yet, but I had assumed a primary operating system will support Sonoma. 

One alternative is to use the MRIcroMTL version. This uses Metal instead of OpenGL so it is in theory an more optimized solution, albeit it does not support all the features.

https://github.com/rordenlab/MRIcroGL/releases/tag/v1.2.20210317